Transmission spectroscopy with VLT FORS2: a featureless spectrum for the low-density transiting exoplanet WASP-88b
Spyratos, P; Nikolov, N; Southworth, J; et al.Constantinou, S; Madhusudhan, N; Carter, AL; de Mooij, EJW; Fortney, JJ; Gibson, NP; Goyal, JM; Helling, C; Mayne, NJ; Mikal-Evans, T
Date: 5 July 2021
Journal
Monthly Notices of the Royal Astronomical Society
Publisher
Oxford University Press (OUP) / Royal Astronomical Society
Publisher DOI
Abstract
We present ground-based optical transmission spectroscopy of the low-density hot Jupiter WASP-88b covering the wavelength range 4413 − 8333 Å with the FORS2 spectrograph on the Very Large Telescope. The FORS2 white light curves exhibit a significant time-correlated noise which we model using a Gaussian Process and remove as a ...
We present ground-based optical transmission spectroscopy of the low-density hot Jupiter WASP-88b covering the wavelength range 4413 − 8333 Å with the FORS2 spectrograph on the Very Large Telescope. The FORS2 white light curves exhibit a significant time-correlated noise which we model using a Gaussian Process and remove as a wavelength-independent component from the spectroscopic light curves. We analyse complementary photometric observations from the Transiting Exoplanet Survey Satellite and refine the system properties and ephemeris. We find a featureless transmission spectrum with increased absorption towards shorter wavelengths. We perform an atmospheric retrieval analysis with the AURA code, finding tentative evidence for haze in the upper atmospheric layers and a lower likelihood for a dense cloud deck. Whilst our retrieval analysis results point toward clouds and hazes, further evidence is needed to definitively reject a clear-sky scenario.
Physics and Astronomy
Faculty of Environment, Science and Economy
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